Here the very general changes that are to be found at the game description, but perhaps it should not be missing:
- level to 70 in a new Continent, and learn new spells
- 2 new races: The interstellar-refugee Draenei (Alliance) and the magic-addicted Blood Elves (Horde). Which now allow to become a Shaman (as Alliance) or Paladin (as Horde).
- You will be able to use a flying mount.

One of the most obvious Quality of Life features that came with Blood Crusade was ... (proper!) Auto Loot functionality.

If a loot box popped up, you automagically looted everything in it. Done.

And while that doesn't sound all that impressive a feature, it was beyond amazing for what it did to the cash flow of Rogues. Now you could create macros for your from Stealth opening attacks that added Pickpocket (which would Auto Loot successfully!) before using your opening attack. You could now Pickpocket and attack all in one action. Likewise, if you didn't want to break Stealth, you could Pickpocket, Auto Loot, and just keep moving ... dramatically reducing the span of time where you were vulnerably close to your target. Made Pickpocketing a breeze to do, and consequently improved the cash flow (and indirectly, Ravenholdt Reputation) of pretty much every Rogue in the game.

Verbogeny is one of many pleasurettes afforded a creatific thinkerizer.